• Journal of Food Hygiene and Safety
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• v.36 no.6
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• pp.493-503
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• 2021

The study was designed to analyze raw and auxiliary materials of Korean traditional cookies such as Yugwa and Gangjeong, equipment and tools, personal hygiene of workers and microbial contamination of materials by each manufacturing process. In addition, it looked at washing method for reducing microorganisms at the site and reduction effect of microorganisms by frequency in the manufacturing processes of Yugwa. In the process of producing Korean traditional cookies, the level of total aerobic bacteria (TAB) in popped rice was 1.2 Log CFU/g and the level of TAB in finished products increased to 3.7 Log CFU/g. In the process of producing Yugwa, the level of TAB increased to a maximum of 6.5 Log CFU/g in the soaking process but decreased to 1.3 Log CFU/g in the frying process. However, the level of TAB increased again to 1.3 Log CFU/g in finished products that proves its recontamination. It is estimated that he manufacturing process causes cross-contamination that comes from the work tools, equipment or workers. In particular, the spatula, one of the work tools, was found to have 4.4 Log CFU/g of aerobic bacteria and 4.2 Log CFU/g of colon bacillus that show they are highly contaminated. In the soaking process of Yugwa that lasts seven days, the level of TAB was a maximum of 10 Log CFU/g and the level of total colon bacillus was 6.8 Log CFU/g. When compared with washing methods, using hands and tools or running water, it is confirmed that the level of both TAB and total colon bacillus decreased to 5.0 Log CFU/g and 2.8 Log CFU/g respectively when hands were washed with running water 10 times. The above result shows that it's required for workers to wash their hands as well as wash and disinfect work tools and equipment in the process of producing Korean traditional cookies at small-scale companies. In addition, to reduce the level of microbial contamination in finished products, workers are required to apply their reduction method at the site.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.10-19
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• 2019

Management plan with repairing is essential for RC structures exposed to chloride attack since durability problems occur with extended service life. Conventionally deterministic method is adopted for evaluation of service life and repair cost, however more reasonable repair cost can be obtained through continuous repair cost from probabilistic maintenance technique. Unlike the previous researches considering only normal distribution of life time, PLTFs (Probabilistic Life Time Function) which can be capable of handling log and normal distributions are attempted for initial and repair service life, and repair cost is evaluated for OPC and GGBFS concrete. PLTF with log distributions in initial service life is more effective to save repair cost since it is more dominant after average than normal distribution. Repair cost in GGBFS concrete decreases to 30% of OPC concrete due to longer initial service life and lower repairing event. The proposed PLTF from the work can handle not only normal distributions but also log distributions for initial and repair service life, so that it can provide more reasonable repair cost evaluation.

• Journal of agriculture & life science
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• v.46 no.3
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• pp.97-108
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• 2012

Physical, chemical and biological hazards of strawberry farms at the cultivation stage were analyzed to establish the GAP(Good Agricultural Practice) system. Samples were collected from the plants, cultivation environments(water, soil and air), and personal hygiene (hand, glove, and clothes) of three strawberry farms(A, B, and C) and were tested to analyze physical, chemical (heavy metals and pesticide residues), and biological(sanitary indications and foodborne pathogens) hazards. Physical hazards such as insects and pieces of metal and glass were found in the strawberry farms and can be potential bow for strawberry products. Heavy metal and pesticide residue as chemical hazards were detected at levels lower than the regulation limit. In case of biological hazards, total bacteria and coliform were detected at the levels of 1.6~7.3 and 1.3~5.6 log CFU/g, leaf, mL, hand or $100cm^2$. However, Escherichia coli was not detected in all samples. Bacillus cereus and Staphylococuus aureus were detected at levels of ${\leq}$ 1.1~6.1 log CFU and 4.7~5.4 log CFU/g, mL, hand or $100cm^2$, whereas Listeria monocytogenes, E. coli O157 and Salmonella spp. were not detected in all samples. This study demonstrates that various harzards were in strawberry farms at the growing stage. Therefore proper management such as GAP is needed to prevent the occurrence of food poisoning associated with the hazards revealed in this study.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.145-152
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• 2000

X-ray diffraction method detects change of crystal lattice distance under material surface using diffraction angle 2$\theta$. This technique can be applied to the behavior on slip band and micro crack due to material degradation. The relation between half-value breadth and number of cycle has three stages which constitute rapid decrease in initial number of cycles, slight decrease in middle number of cycles and rapid decrease in final number of cycles. The ratio of half-value breadth takes a constant value on B/B$_{0}$-N diagram with loading condition except early part of fatigue life. The ratio of half-value breadth B/B$_{0}$ with respect to number of cycle to failure N$_{f}$ has linear behavior on B/B$_{0}$-log N$_{f}$ diagram. Therefore, in this paper the estimation of fatigue life by average gradient method has much less estimated mean error than the estimation of fatigue life by log B/B$_{0}$-log N/N$_{f}$ relation.elation.ation.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.54-60
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• 2008

Sound absorption coefficients of oak (Quercus mongolica) wood and oak mushroom bed log were measured by the two microphone transfer function method and anatomical features of oak mushroom bed log examined by stereo scope and SEM observations. The sound absorption coefficients of oak mushroom bed log seemed to be higher than those of normal oak wood specimen over all estimated frequency range. Especially, in the frequency range of 2 to 6 kHz, they were about 2~3 times higher than those of normal wood specimen. Due to fungi degradation, the specific gravity of oak mushroom bed log decreased about 70% than that of normal wood. For oak mushroom bed log, abundant pores occurred on the radial, tangential and cross sectional surface and it was considered that the pores behaved as a sound absorbing pore.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.210-214
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• 2009

This study identified microbial risk factors in agricultural products processing center (APC) through the microbial hazard analysis to introduce good agricultural practices (GAP) system in APCs. Samples were collected from surroundings (basket, tray loader, weighing cup, collector, box) and workers by swabbing (glove and cloth) and glove juice method (hand) to enumerate total bacteria, coliform, Staphylococcus aureus, Escherichia coli, Escherichia coli O157:H7 and Salmonella. The levels of total bacterial and coliform populations recovered from surroundings were 2.4-5.7 log CFU/100 $cm^2$ and 2.3-5.7 log CFU/100 $cm^2$ or hand for surroundings, and workers, respectively samples were 2.3-5.7 log CFU/100 $cm^2$ or hand. Escherichia coli populations were determined to be below detection limit. S. aureus and Salmonella populations recovered from surroundings were 3.0-4.4 log CFU/100 $cm^2$ and close to detection limit, respectively. Corresponding bacterial populations to worker's samples were 2.8-5.2 log CFU/100 $cm^2$ or hand (S. aureus) and below detection limit (Salmonella). Bacterial populations of APC certified facilities were similar (p${\geq}$0.05) with those of uncertified facilities. These results showed that this study should be useful in development of GAP models to improve microbial safety in APCs.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.99-106
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• 2012

In recent years, many researchers studies to promote the welfare of disabled people using IT technology. In particular, their suggestions are used a lot of mobile sensor installed on the street. These systems are acquired and to store the data sent to the server over the network, and by analyzing the users life log to judge of their risk state. In particular, persons with disabilities are exposed to various risks. So, they must need to the guardians if he go out. Thus, this study is a method for alleviating these so much pressure to smart appliances and impaired life log analysis system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.5
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• pp.894-898
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• 2004

This study was carried out to determine the optimum irradiation dose for infant foods with improved energy-density and extend shelf-life using gamma irradiation. Rice and rice porridge were irradiated at 0, 2.5, 5, 7.5, 10, 15 and 20 kGy, and rheological characteristics and total plate count of porridge were evaluated for 6 weeks. Rice and rice porridge at 2.5 kGy dose reduced the viscosity with 22% and 98%, respectively. The result of total aerobic bacteria of non-irradiated rice porridge was 6 log CFU/g and that of 2.5 kGy irradiated rice porridge on 2 weeks storage was 3 log CFU/g, while that of 7.5 kGy irradiated sample was not detected even at the end of storage. Irradiation on rice-based porridge was proper to enhance the total solid in inverse proportion to considering viscosity and extend shelf-life. Gamma irradiation was effective technology in enhancing calorie value of porridge due to reduction of viscosity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.245-252
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• 2011

The combined effects of 10 kJ/$m^2$ ultraviolet-C (UV-C) with 50 ppm aqueous chlorine dioxide ($ClO_2$) on the qualities of red chicory and pak choi were examined. After the treatment, the samples were stored at $4{\pm}1^{\circ}C$ for 7 days. The combined treatment of $ClO_2$/UV-C reduced the initial populations of total aerobic bacteria in the red chicory and pak choi by 2.64 and 2.55 log CFU/g, respectively, compared to those of the control. Also, the populations of yeast and molds in the red chicory and pak choi by combined treatment were reduced by 2.41 and 2.00 log CFU/g, respectively. In addition, after 7 days of storage the total aerobic bacteria populations in the red chicory and pak choi were reduced to 3.71 and 3.93 log CFU/g, compared to 6.31 and 6.62 log CFU/g for the control, resulting in a significant decrease. Hunter L, a, and b values of red chicory and pak choi were not significantly different among the treatments. Non-thermal treatment caused a negligible change in sensory evaluation. These results suggest that the combined treatment of 50 ppm $ClO_2$ with 10 kJ/$m^2$ UV-C can be useful for maintaining the qualities of red chicory and pak choi.

• Journal of Applied Reliability
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• v.14 no.1
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• pp.45-51
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• 2014

Thermal shock tests at two stress levels were performed to see the life (cycles) of LPF ASSY (low pass filter assembly) at normal stress level. In this case Coffin-Manson relationship is generally used to describe the relationship between the temperature difference and the life, together with the Weibull distribution describing the life at each stress level. So for given data Coffin-Manson is fitted to predict the life at normal stress level. However, different types of models are appropriate for this type of test. Hence, a more appropriate model such as General log-linear model which can also incorporate the duration at the highest and lowest temperatures and acceleration time will be introduced.